The present disclosure relates to an image forming apparatus.
In an image forming apparatus such as a copy machine, a printer, a facsimile machine, or a multifunction peripheral, it is known that when an electrostatic latent image is formed on a photosensitive drum in accordance with image data, a development electric field intensity at an end portion of an image increases due to edge effect, and the toner amount used for development increases. Further, a halo effect is also known in which, at a portion where an outputted image changes from a low-density portion to a high-density portion in the sub scanning direction, toner moves from the low-density portion to the high-density portion, whereby the density at a rear end portion of the low-density portion, that contacts the high-density portion, decreases.
One image forming apparatus detects density change in the advancing direction of an image carrier, and performs light amount correction to gradually decrease the light amount from the boundary of the density change.
Another image forming apparatus forms a patch having a high-density portion and a low-density portion that are close to each other, detects image defect at the boundary between the high-density portion and the low-density portion, and controls a development bias and the like, thereby correcting the image defect at the boundary between the high-density portion and the low-density portion.
Still another image forming apparatus changes an image formation condition (particularly, development sleeve rotation rate, doctor blade gap, distance between drum and development sleeve, etc.) in accordance with characteristics change in a region from a halftone portion to a solid portion.
Still another image forming apparatus forms a high-density image and a low-density image having an edge intersecting with the movement direction of a transfer body, and performs discharge and supply of toner of a developing device based on the density at the adjacent portion therebetween.
Still another image forming apparatus adjusts the exposure amount based on a result of detection by means for detecting an edge at which a high-density region and a low-density region in an image pattern are adjacent to each other.
Still another image forming apparatus detects, as reflected light amount, the density at a rear end portion of a toner patch image formed on a photosensitive drum, and controls a grid application voltage and a development bias.